lol didn't know that about Sweden (link or data pls? not like I expect it to exist), but see the same with rich liberals in coastal enclaves in the US (Malibu, Martha's Vineyard).
I do not think it is a study other than the observed tendency, there are about white flight in general and it being correlated with political leaning not actual lived experience.
While people in actually diverse places (southwest, south) getting along or working though differences. (Open borders/illegal immigration being different than racial diversity).
Sure, because they have a common culture and they are working class faced with the universal struggle of every day life, the problem is multiculturalism and lack of assimilation.
A lot of the vitriol and outrage comes from people outside the states that look in and spin some story about there being a caste system of sorts, but there are no borders inside US.
It mostly comes from countries that are small and not diverse in culture or race, so they see that over half of the convicted murderers is black and conclude that police is racist.
notice a similar general trend in US. People in very white states (pacific northwest, NH) advocating for diversity but not living it. (All talk no action).